How to initiate insulin therapy in patients on high dose glucocorticoids (steroids)?

Initiating Insulin Therapy in Patients on High-Dose Glucocorticoids

For patients on high-dose glucocorticoids, initiate insulin therapy with NPH insulin at 0.3 units/kg per day (giving 2/3 in the morning and 1/3 in early evening), plus consider additional prandial insulin coverage for optimal glycemic control. 1

Understanding Glucocorticoid-Induced Hyperglycemia

• Glucocorticoid use is common in hospitalized patients and can induce hyperglycemia in 56-86% of individuals with and without preexisting diabetes 1
• When higher doses of steroids are used, afternoon and evening hyperglycemia are particularly common due to the pharmacokinetic profile of glucocorticoids 1
• Untreated steroid-induced hyperglycemia increases mortality and morbidity risk, including infections and cardiovascular events 1

Insulin Regimen Selection Based on Glucocorticoid Type

For Intermediate-Acting Glucocorticoids (e.g., Prednisone)

• NPH insulin is the preferred choice for once-daily morning prednisone due to its intermediate-acting profile that peaks at 4-6 hours, aligning with the peak hyperglycemic effect of glucocorticoids 1
• Administer NPH concomitantly with intermediate-acting steroids to match the timing of peak insulin action with peak steroid-induced hyperglycemia 1

For Long-Acting Glucocorticoids (e.g., Dexamethasone)

• Long-acting basal insulin may be required to manage fasting blood glucose levels 1
• Consider a combination approach that includes both long-acting insulin and NPH insulin for more comprehensive coverage 2

Initial Dosing Algorithm

For Patients Without Diabetes:

• For non-diabetic patients with steroid-induced hyperglycemia, a single dose of NPH insulin in the morning might be appropriate 1
• Start with NPH insulin at 0.1-0.2 units/kg per day if blood glucose readings exceed 13.9 mmol/L (250 mg/dL) 1

For Patients With Pre-existing Diabetes:

• Multiple-dose insulin therapy initiated at 1-1.2 U/kg per day, distributed as 25% basal and 75% prandial insulin 1
• Add NPH insulin (0.1-0.3 U/kg per day) to the usual insulin regimen, with doses determined according to steroid dose and oral intake 1
• For high-dose dexamethasone, use NPH insulin twice daily (for more flexibility in dose adjustment) with a total dose of 0.3 units/kg per day 1

Practical Administration Schedule

• Give 2/3 of the total daily NPH dose in the morning and the remaining 1/3 in the early evening 1
• For higher doses of glucocorticoids, increase prandial (if eating) and correctional insulin doses by 40-60% in addition to basal insulin 1
• For patients receiving enteral/parenteral nutrition while on steroids, NPH insulin can be administered two or three times daily (every 8 or 12 hours) 1

Monitoring and Dose Adjustments

• Monitor blood glucose every 2-4 hours while the patient is hospitalized to guide insulin adjustments 2
• Target blood glucose range should be 100-180 mg/dL (5.6-10.0 mmol/L) 1, 2
• For persistent hyperglycemia, increase NPH dose by 2 units every 3 days until target blood glucose is achieved 2, 3
• Insulin requirements can decline rapidly after glucocorticoids are stopped, requiring prompt dose adjustments to avoid hypoglycemia 1

Common Pitfalls to Avoid

• Avoid relying solely on sliding scale insulin, which is associated with poor glycemic control 2, 4
• Beware of hypoglycemia risk when adjusting insulin doses, especially in patients with decreased oral intake 4, 3
• Sulfonylureas are not recommended for managing glucocorticoid-induced hyperglycemia 1
• When holding glucocorticoids, reduce NPH insulin by 20% immediately to prevent hypoglycemia 5

Special Considerations

• For patients on continuous glucocorticoid therapy, a basal-bolus approach has shown adequate glycemic control in clinical trials 1, 4
• In a retrospective study, bolus-only insulin regimens showed lower risk of hypoglycemia compared to basal-bolus or premixed insulin regimens, though this contradicts current guidelines 4
• For patients already on insulin therapy, increasing the total daily dose by at least 30% when starting glucocorticoids is recommended 5, 3

By following this structured approach to insulin initiation in patients on high-dose glucocorticoids, you can effectively manage steroid-induced hyperglycemia while minimizing the risk of complications.